Sunday, January 13, 2008

Home Automation Resource management

A couple of interesting articles both from the N.Y Times. The first is California Seeks Thermostat Control - the gist of the story is that the California Energy Commission wants to be able to control the temperature of your HVAC to 'manage electricity shortages'. The second article is similar but from a different point of view: Digital Tools Help Users Save Energy, Study Finds - the gist of this story is that if the end users are given tools to monitor their electrical usage they will regulate themselves. Or to put it another way they'll spend their money more wisely.

The first story is a scary story because I fear what I don't know. What I don't know are the rules for when they can change my thermostat. The idea that things inside my home can be controlled without my knowledge or approval scares me. My biggest concern is "Will the protocol to control my thermostat be properly secure"? Security as an after thought is a common occurrence in electronics and computers. The second story is more and less scary at the same time. This time the information is out on the Internet which means that someone can be watching you. For what reason I don't know. It's just that I don't trust utility companies with information security. Ease of use may be their first concern and security plays second string to ease of use. Also it seems that anytime someone gathers information about you or your usage patterns it is no longer your information and they can sell it as they see fit. That I object to. What I like about the "digital tools" idea is that it gives the consumer the option to spend their money wisely. What I'd like to see is every outlet have a power monitor and not just the total incoming power being monitored. Something that will give me information about the usage of devices on that outlet. I can then plot usage patterns, looks for trends, monitor past performance and predict end of life for a device. What I mean by end of life is when I can replace the current device because it appears to be wearing out or when it appears I can save money by replacing it with a more efficient device. All of this is goes into the information processing/resource management portion of my HA definition (which you can find here).

Overall I think this will come to everyone. At seven billion+ people we need to find ways to manage our resources. If we don't do it ourselves then someone will do it for us. I prefer to remain in control of my choices as I am the only one who knows what's best for me.

For those who may be wondering: 'how can something like this be done?', let me explain. First gather the data, Dr. Edward Cheung created a Power Monitor which is perfect for this. Where as some power monitoring devices monitor just the current usage and then multiple by the fixed AC voltage, Dr. Cheung's device measures the instantaneous AC voltage and current at a given time. Once we have the power data we store it in a database. Next we can plot the usage and use the values to calculate various thing such as daily, weekly, monthly, and yearly. Throw in some derivatives (yes calculus has a lot of uses :-) and some canned formulas and you can calculate all sort of interesting and useful information. Under Linux I can automate this by using mysql (database), Perl and Expect (as my parsing language) and a non-GUI spread sheet (SC) to do my calculations. Finally I use GNU Plot to plot the data to a web page that I can post to the internet or my private in-house web site. One of these days I'll learn enough AJAX and be able to do some 'what-if' calculations from the web site. If I need a faster interface I can still use OO Spread Sheet or Gnumeric (my preferred GUI base Spread Sheet). Windows users can do the same things, none of this is tied to an operating system.


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